Track-type undercarriages, such as those individually having either a track chain or an elastomeric belt entrained about a drive wheel, are known to exhibit superior performance characteristics in certain respects over wheel suspension systems. These track-type undercarriages provide reduced ground pressure per unit area of contact and increased traction. Moreover, uneven and soft terrain vehicles equipped with track-type undercarriage have improved flotation and stability, and are more efficient than wheeled vehicles.
It has been found that many combine harvesters equipped with wheels could not be operated under wet and muddy conditions at the time the crop was ready to be harvested. In order to overcome this significant agricultural problem, it is desirable to replace the wheels with a belt-type undercarriage. This has enabled the combine to traverse safely over soft ground because the weight is more evenly distributed through the undercarriage and belt. Exemplifying this type of machine is U.S. Pat. No. 4,781,257 issued to Gee et al on Nov. 1, 1988 and U.S. Pat. No. 5,018,591 issued to Price on May 28, 1991.
Harvesters typically have a relatively light superstructure frame utilizing thin beams, diagonal braces, and plates. The superstructure can be subjected to relatively high dynamic twisting and bending forces as the machine moves over rough terrain.
Therefore, what is desired is a suspension structure for a tracked machine such as a combine harvester that eliminates twisting forces from being transferred up to the superstructure and to provide cushioning and damping for the superstructure.
The present invention is directed to overcome one or more of the problems as set forth above.